As expected, Subtropical Storm Nicole formed Monday, and is predicted to both become tropical and to hit Florida this week. It's just a matter of the details. It may not look like much now, but winds and seas are already increasing significantly:
First of all, even though the location and track of this November tropical storm are rare, it is NOT unprecedented-anyone who says that isn't looking at history. An even "weirder" track occurred in November 1935, when the "Yankee Hurricane" formed east of Bermuda but ended up hitting Miami as a Category 2 hurricane. It was supposedly called "Yankee" because it came from the north (which virtually never happens with a hurricane).
The predicted track of Nicole is almost as weird, as the 5pm Monday advisory from NHC shows:
Even though it's unusual, it's pretty much a sure thing that Nicole will make a direct hit on the east coast of Florida, probably on Thursday. It will also cause tropical storm force winds (39+ mph) over much of the Florida east coast, and probably Georgia and even South Carolina. That's a HUGE area. This same area will also experience significant coastal flooding due to:
- The track. Straight east to west means more than 500 miles of east winds build up ocean waves before Nicole hits
- Late strengthening. Nicole will likely strengthen to near hurricane strength
- Multiple high tides with coastal flooding made even worse due to the full moon this week. Damaging storm surges are likely just north of where the eye of Nicole makes landfall.
It is going to take a while for Nicole to start intensifying. There's still too much dry air nearby. But water temperatures are plenty high enough and extend to enough of a depth to insure it happens.
In fact, it's a "marine heat wave" east of Florida, with near record "ocean heat content" for this late in the season:
This is one ingredient that has changed a lot since 1935-the ocean is far warmer. And a paper just published days ago shows the result of this warmth: tropical storms and hurricanes are intensifying faster off the east coast of the U.S. due to the changed climate...
Atlantic Coast Hurricanes Intensifying Faster Than Forty Years Ago
New NOAA research published in the journal Geophysical Research Letters, found that hurricane intensification rates near the U.S. Atlantic coast have increased significantly over the last 40 years and will likely continue to increase in the future.
Landfalling hurricanes can cause loss of life and severe damage, and when these storms intensify near the coast causing winds to increase, they can pose a more serious threat and represent a bigger challenge for damage mitigation.
Using observations and climate model simulations, scientists at NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) analyzed hurricane intensification patterns in the 230 mile area of the shoreline using storm track data for a 40-year period from 1979–2018. The study found the average intensification rate increased by about 1.3 miles per hour near the U.S. Atlantic coast. Researchers did not find a significant increase in hurricane intensity near the Gulf of Mexico coast over the same period.
Climate models used in the study show that hurricanes near the U.S. Atlantic coast enter into an increasingly favorable environment just ahead of landfall, which can cause storm wind speeds, or intensity, to increase quickly. A favorable pressure gradient across the land-sea boundary, warming ocean temperatures, and decreasing vertical wind shear (the change in the wind’s direction and speed with height) are all factors that make it easier for hurricanes to intensify.
The upper-air pattern is also cause for some concern. As we showed in yesterday's column, this is known as a "Rex Block", with unusually high pressure to the north and low pressure to the south. Here is the pattern for Wednesday, and then a classic example from the National Weather Service:
These blocking patterns are notorious for leading to extreme weather-somewhere. It's too early to tell exactly what place will experience the worst. But don't let the "mere tropical storm" or "minimal hurricane" language from some folks keep your guard down.
— Glenn "Hurricane" Schwartz email@example.com
What you need to know, currently.
The National Hurricane Center has issued a hurricane watch for Florida’s east coast — from the Brevard-Volusia county line, south to Hallandale Beach — as subtropical storm Nicole developed Monday morning in the Atlantic Ocean. A tropical storm watch has also been issued for northeastern Florida, southeastern Florida and southeastern Georgia.
The storm is expected to become a hurricane by 8 p.m. ET on Wednesday, before it comes to Florida’s west coast, hitting the Bahamas on its way. The storm’s magnitude is still uncertain.
“The main difference between a tropical and subtropical storm is not in the winds that they generate, but that a tropical storm tends to generate more rain,” says Currently’s Chief Meteorologist, Megan Montero.
There will be heavy rainfall through Thursday across the Florida peninsula, as well as flash and urban flooding. Dangerous storm surge is also possible across the northwestern Bahamas, the east coast of Florida and areas of coastal Georgia, according to Montero.
The National Oceanic and Atmospheric Administration has predicted at least four more hurricanes will form before the season officially ends on Nov. 30. The next named storm to form would be Owen.